<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
      <div class="iconfont back-abs-back">&#xe743;</div>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      城市选择
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe743;</div>
      </router-link>
    </div>
  </div>
</template>
<script>

export default {
  name: 'DetailHeader',
  components: {
  },
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  unactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>
<style lang='stylus' scoped>
@import '~styles/varibles.styl';
@import '~styles/mixins.styl';

.header-fixed {
  z-index: 2;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  overflow: hidden;
  height: $headerHeight;
  line-height: 0.86rem;
  text-align: center;
  color: #fff;
  background-color: $bgcolor;
  font-size: 0.3rem;
  ellipsis();
}

.header-fixed-back {
  position: absolute;
  top: 0;
  left: 0;
  width: 0.64rem;
  margin-left: 0.12rem;
  text-align: center;
  font-size: 0.6rem;
  color: #fff;
}

.header-abs {
  position: absolute;
  left: 0.2rem;
  top: 0.2rem;
  width: 0.6rem;
  height: 0.6rem;
  line-height: 0.6rem;
  border-radius: 0.3rem;
  text-align: center;
  background: rgba(0, 0, 0, 0.8);
}

.back-abs-back {
  color: #fff;
  font-size: 0.5rem;
}
</style>
